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<head><meta charset="utf-8"><title>weekly meeting 2019.02.27 · t-compiler/wg-nll · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/index.html">t-compiler/wg-nll</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html">weekly meeting 2019.02.27</a></h3>

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<a name="159512370"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159512370" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159512370">(Feb 27 2019 at 13:36)</a>:</h4>
<p>hi <span class="user-group-mention" data-user-group-id="491">@WG-compiler-nll</span> ; we'll be having our meeting in this stream topic in about ... seven hours.</p>



<a name="159512696"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159512696" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159512696">(Feb 27 2019 at 13:38)</a>:</h4>
<p>as discussed last week, the weekly meeting is going to shift to more of a synchronized office hours of sorts. But I still want to take care of pre-triage before the meeting; I've dedicated a <a href="#narrow/stream/122657-t-compiler.2Fwg-nll/topic/pre-triage.202019.2E02.2E27/near/159512514" title="#narrow/stream/122657-t-compiler.2Fwg-nll/topic/pre-triage.202019.2E02.2E27/near/159512514">separate topic</a> to that task.</p>



<a name="159528278"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159528278" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159528278">(Feb 27 2019 at 16:17)</a>:</h4>
<p>pre-triage is done. The outcome is <a href="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=+label%3AA-NLL+label%3AI-nominated+" target="_blank" title="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=+label%3AA-NLL+label%3AI-nominated+">five nominated issues/prs</a> to discuss at tonight's meeting.</p>



<a name="159531665"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159531665" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159531665">(Feb 27 2019 at 16:52)</a>:</h4>
<p>does "synchronized office hours of sorts" mean "we'll generally talk about issues, ask questions, think about how to solve them ?"</p>



<a name="159549372"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549372" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549372">(Feb 27 2019 at 20:25)</a>:</h4>
<p>seems reasonable to me</p>



<a name="159549433"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549433" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549433">(Feb 27 2019 at 20:26)</a>:</h4>
<p>okay <span class="user-group-mention" data-user-group-id="491">@WG-compiler-nll</span> , you got your seven hour warning, now this is your five minute warning. :)</p>



<a name="159549477"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549477" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549477">(Feb 27 2019 at 20:27)</a>:</h4>
<p>Currently compiling what I hope is a fix for <a href="https://github.com/rust-lang/rust/issues/58776" target="_blank" title="https://github.com/rust-lang/rust/issues/58776">#58776</a></p>



<a name="159549785"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549785" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549785">(Feb 27 2019 at 20:31)</a>:</h4>
<p>Hi everyone</p>



<a name="159549818"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549818" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549818">(Feb 27 2019 at 20:31)</a>:</h4>
<p>as noted <a href="#narrow/stream/122657-t-compiler.2Fwg-nll/topic/weekly.20meeting.202019.2E02.2E27/near/159528278" title="#narrow/stream/122657-t-compiler.2Fwg-nll/topic/weekly.20meeting.202019.2E02.2E27/near/159528278">above</a>, pre-triage yielded five nominated issues</p>



<a name="159549846"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549846" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549846">(Feb 27 2019 at 20:32)</a>:</h4>
<p>I'm hoping we can get through them relatively quickly and then leave the remaining time to free discussion</p>



<a name="159549909"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549909" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549909">(Feb 27 2019 at 20:32)</a>:</h4>
<p>the nominated issues are <a href="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=+label%3AA-NLL+label%3AI-nominated+" target="_blank" title="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=+label%3AA-NLL+label%3AI-nominated+">these five</a></p>



<a name="159549935"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549935" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549935">(Feb 27 2019 at 20:32)</a>:</h4>
<p>first is "NLL migrate mode erroneously downgrades error with nested closures, yielding use-after-free" <a href="https://github.com/rust-lang/rust/issues/58776" target="_blank" title="https://github.com/rust-lang/rust/issues/58776">#58776</a>, which sounds like its hopefully under control</p>



<a name="159549942"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549942" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549942">(Feb 27 2019 at 20:32)</a>:</h4>
<p>in any case its clear that <span class="user-mention" data-user-id="116118">@Matthew Jasper</span> is on the case</p>



<a name="159549968"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549968" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549968">(Feb 27 2019 at 20:33)</a>:</h4>
<p>so I'm just going to remove the nominated tag; if anyone has Q's about it, lets maybe have those after we go through the other nominations</p>



<a name="159549990"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549990" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549990">(Feb 27 2019 at 20:33)</a>:</h4>
<p>going slightly out of order, next is "Include bounds from promoted constants in NLL" <a href="https://github.com/rust-lang/rust/issues/57202" target="_blank" title="https://github.com/rust-lang/rust/issues/57202">#57202</a></p>



<a name="159549995"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159549995" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159549995">(Feb 27 2019 at 20:33)</a>:</h4>
<p>I nominated this after reviewing it today</p>



<a name="159550055"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550055" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550055">(Feb 27 2019 at 20:34)</a>:</h4>
<p>because I just wanted to point out that this change is going to change our handling of a particular test case</p>



<a name="159550072"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550072" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550072">(Feb 27 2019 at 20:34)</a>:</h4>
<p>as i commented <a href="https://github.com/rust-lang/rust/pull/57202#discussion_r260790519" target="_blank" title="https://github.com/rust-lang/rust/pull/57202#discussion_r260790519">here</a> in my review</p>



<a name="159550082"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550082" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550082">(Feb 27 2019 at 20:34)</a>:</h4>
<p>seems like it ICEd in some tests ?</p>



<a name="159550083"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550083" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550083">(Feb 27 2019 at 20:34)</a>:</h4>
<p>so the test in question is from issue <a href="https://github.com/rust-lang/rust/issues/48697" target="_blank" title="https://github.com/rust-lang/rust/issues/48697">#48697</a></p>



<a name="159550109"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550109" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550109">(Feb 27 2019 at 20:35)</a>:</h4>
<blockquote>
<p>seems like it ICEd in some tests ?</p>
</blockquote>
<p>hmm clearly we'll have to look into that too</p>



<a name="159550188"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550188" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550188">(Feb 27 2019 at 20:36)</a>:</h4>
<div class="codehilite"><pre><span></span>[00:26:48] thread &#39;rustc&#39; panicked at &#39;index out of bounds: the len is 0 but the index is 0&#39;, /checkout/src/libcore/slice/mod.rs:2539:10
[00:26:48] note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
[00:26:48]
[00:26:48] error: internal compiler error: unexpected panic
[00:26:48]
[00:26:48] note: the compiler unexpectedly panicked. this is a bug.
</pre></div>



<a name="159550201"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550201" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550201">(Feb 27 2019 at 20:36)</a>:</h4>
<p>lack of a stack trace there is unfortunate</p>



<a name="159550204"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550204" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550204">(Feb 27 2019 at 20:36)</a>:</h4>
<p>Yes, that's from a rebase. I'll have a look soon.</p>



<a name="159550211"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550211" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550211">(Feb 27 2019 at 20:36)</a>:</h4>
<p>any way I personally am okay with the shift in behavior in the test</p>



<a name="159550230"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550230" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550230">(Feb 27 2019 at 20:37)</a>:</h4>
<p>though it might good to validate the hypothesis I posted as to <em>why</em> its not compiling now</p>



<a name="159550241"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550241" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550241">(Feb 27 2019 at 20:37)</a>:</h4>
<p>The test was to check that we didn't ICE</p>



<a name="159550247"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550247" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550247">(Feb 27 2019 at 20:37)</a>:</h4>
<p>right. and we don't ICE</p>



<a name="159550255"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550255" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550255">(Feb 27 2019 at 20:37)</a>:</h4>
<p>but still, it <em>is</em> a change in the static semantics. Its probably a bug fix</p>



<a name="159550310"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550310" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550310">(Feb 27 2019 at 20:38)</a>:</h4>
<blockquote>
<p>though it might good to validate the hypothesis I posted as to <em>why</em> its not compiling now</p>
</blockquote>
<p>it <em>is</em> compiling now ?</p>



<a name="159550313"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550313" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550313">(Feb 27 2019 at 20:38)</a>:</h4>
<p>tell you what, I'll just give myself an action item to double-check why its behavior changed</p>



<a name="159550327"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550327" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550327">(Feb 27 2019 at 20:38)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> <a href="http://issue-48697.rs" target="_blank" title="http://issue-48697.rs">issue-48697.rs</a> compiles on current master. After this PR, it gets rejected with a static error</p>



<a name="159550333"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550333" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550333">(Feb 27 2019 at 20:38)</a>:</h4>
<p>ah understood</p>



<a name="159550357"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550357" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550357">(Feb 27 2019 at 20:39)</a>:</h4>
<p>or ... well the commit I had commented on may have dissapeared</p>



<a name="159550363"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550363" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550363">(Feb 27 2019 at 20:39)</a>:</h4>
<p>but I assuem that it an artifact of rebasing</p>



<a name="159550420"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550420" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550420">(Feb 27 2019 at 20:40)</a>:</h4>
<p>maybe this is stable <a href="https://github.com/rust-lang/rust/pull/57202/files#diff-91652dffff87bfbf9b4392ae57c61778L3" target="_blank" title="https://github.com/rust-lang/rust/pull/57202/files#diff-91652dffff87bfbf9b4392ae57c61778L3">diff link</a> ?</p>



<a name="159550437"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550437" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550437">(Feb 27 2019 at 20:40)</a>:</h4>
<p>anyway. I'll work on satisfying my own curiosity here</p>



<a name="159550447"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550447" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550447">(Feb 27 2019 at 20:40)</a>:</h4>
<p>I'm not so concerned about this one as to try to push for a warning cycle or whatnot</p>



<a name="159550454"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550454" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550454">(Feb 27 2019 at 20:40)</a>:</h4>
<p>(this case was already being rejected by AST-borrowck)</p>



<a name="159550472"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550472" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550472">(Feb 27 2019 at 20:41)</a>:</h4>
<p>next nominated issue: "user type annotations are captured post normalization" <a href="https://github.com/rust-lang/rust/issues/54940" target="_blank" title="https://github.com/rust-lang/rust/issues/54940">#54940</a></p>



<a name="159550484"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550484" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550484">(Feb 27 2019 at 20:41)</a>:</h4>
<p>I nominated this in the hopes that niko might be able to report what the plan is for lazy normalization</p>



<a name="159550493"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550493" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550493">(Feb 27 2019 at 20:41)</a>:</h4>
<p>which he has said is blocking this from being fixed</p>



<a name="159550495"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550495" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550495">(Feb 27 2019 at 20:42)</a>:</h4>
<p>but I don't think <span class="user-mention" data-user-id="116009">@nikomatsakis</span> is here right now</p>



<a name="159550540"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550540" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550540">(Feb 27 2019 at 20:42)</a>:</h4>
<p>I can just leave this nominated but we can move along</p>



<a name="159550542"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550542" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550542">(Feb 27 2019 at 20:42)</a>:</h4>
<p>I sort of am</p>



<a name="159550546"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550546" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550546">(Feb 27 2019 at 20:42)</a>:</h4>
<p>I've not been following along (sorry)</p>



<a name="159550556"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550556" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550556">(Feb 27 2019 at 20:42)</a>:</h4>
<p>they were recently looking for examples of things needing lazy norm</p>



<a name="159550566"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550566" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550566">(Feb 27 2019 at 20:42)</a>:</h4>
<p>its sort of a cross-cutting issue at this point</p>



<a name="159550567"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550567" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550567">(Feb 27 2019 at 20:42)</a>:</h4>
<p>Ah, lazy norm -- well, answer is that I am currently in an "investigative" phase -- and that's it's a high priority of traits WG</p>



<a name="159550568"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550568" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550568">(Feb 27 2019 at 20:42)</a>:</h4>
<p>between WG-nll and WG-traits</p>



<a name="159550573"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550573" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550573">(Feb 27 2019 at 20:43)</a>:</h4>
<p>but still haven't formed concrete plan of what we will do</p>



<a name="159550587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550587">(Feb 27 2019 at 20:43)</a>:</h4>
<p>but "progress is being made"</p>



<a name="159550594"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550594" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550594">(Feb 27 2019 at 20:43)</a>:</h4>
<p>so maybe Ill just leave it nominated and we can maybe hope to discuss tomorrow at T-compiler meeting?</p>



<a name="159550615"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550615" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550615">(Feb 27 2019 at 20:43)</a>:</h4>
<p>seems ok; I probaly won't have a lot more to say by then, but maybe I can pester some folks :)</p>



<a name="159550619"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550619" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550619">(Feb 27 2019 at 20:43)</a>:</h4>
<p>okay, i can't ask for more than that</p>



<a name="159550630"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550630" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550630">(Feb 27 2019 at 20:43)</a>:</h4>
<p>next nomination: "fix "bivariant wf" bug in the NLL subtyping code" <a href="https://github.com/rust-lang/rust/issues/54105" target="_blank" title="https://github.com/rust-lang/rust/issues/54105">#54105</a></p>



<a name="159550681"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550681" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550681">(Feb 27 2019 at 20:44)</a>:</h4>
<p>I nominated this to see if I could entice a <del>victim</del> volunteer to try to search for a test case</p>



<a name="159550714"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550714" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550714">(Feb 27 2019 at 20:44)</a>:</h4>
<p>with the warning that niko had already put K units of effort (for unspecified K and unspecified work unit) into trying to find said test</p>



<a name="159550738"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550738" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550738">(Feb 27 2019 at 20:45)</a>:</h4>
<p>this might be a better candidate for the free discussion period...</p>



<a name="159550741"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550741" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550741">(Feb 27 2019 at 20:45)</a>:</h4>
<p>in fact</p>



<a name="159550747"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550747" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550747">(Feb 27 2019 at 20:45)</a>:</h4>
<p>I regret bringing it up now;</p>



<a name="159550754"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550754" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550754">(Feb 27 2019 at 20:45)</a>:</h4>
<p>I'd rather raise the last nominated issue first</p>



<a name="159550758"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550758" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550758">(Feb 27 2019 at 20:45)</a>:</h4>
<p>are we sure there is such a bug ? that is, can we find this test case ?</p>



<a name="159550780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550780">(Feb 27 2019 at 20:45)</a>:</h4>
<blockquote>
<p>are we sure there is such a bug ? that is, can we find this test case ?</p>
</blockquote>
<p>that's basically the problem. <span aria-label="smile" class="emoji emoji-263a" role="img" title="smile">:smile:</span></p>



<a name="159550847"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550847" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550847">(Feb 27 2019 at 20:46)</a>:</h4>
<p>our hope was to find a test case; at least for me, that would help assign a prioritization</p>



<a name="159550852"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550852" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550852">(Feb 27 2019 at 20:46)</a>:</h4>
<p>I think <span class="user-mention" data-user-id="116009">@nikomatsakis</span> thinks that there is a bug, but doesn't know if it affects any code.</p>



<a name="159550873"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550873" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550873">(Feb 27 2019 at 20:46)</a>:</h4>
<p>without a test case, its hard for me to give a serious priority label to this, which means I'd be tempted to just tag it as P-low</p>



<a name="159550889"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550889" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550889">(Feb 27 2019 at 20:47)</a>:</h4>
<p>(which is sort of how we've been treating that bug anyway...)</p>



<a name="159550936"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550936" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550936">(Feb 27 2019 at 20:47)</a>:</h4>
<p>anyway I've satisfied my desire to at least publicly state "hey this bug exists"</p>



<a name="159550994"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159550994" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159550994">(Feb 27 2019 at 20:48)</a>:</h4>
<p>so now the last nominated topic, which may be so dumb as to not be worth discussing, is "Does the MIR generated for match still build in order-deps visible to MIR-borrowck?" <a href="https://github.com/rust-lang/rust/issues/58646" target="_blank" title="https://github.com/rust-lang/rust/issues/58646">#58646</a></p>



<a name="159551017"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551017" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551017">(Feb 27 2019 at 20:49)</a>:</h4>
<p>so this one I think requires a little bit of explanation; you can find an attempt at an explanation on the bug description</p>



<a name="159551125"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551125" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551125">(Feb 27 2019 at 20:50)</a>:</h4>
<p>(about the prior issue: maybe we can look for such a case in a relaxed/exploratory manner ? that is, I'm not opposed to looking for such a thing myself but if Niko didn't find it easily after some K units of time I'm not particularly hopeful about my chances :)</p>



<a name="159551147"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551147" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551147">(Feb 27 2019 at 20:50)</a>:</h4>
<p>but the heart of <a href="https://github.com/rust-lang/rust/issues/58646" target="_blank" title="https://github.com/rust-lang/rust/issues/58646">#58646</a> is: we have some amount of safe-guards against accidental order-dependence in our code-generation for match. That is, we don't want to couple ourselves too tightly to the particular control-flow graph that we happen to generate</p>



<a name="159551195"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551195" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551195">(Feb 27 2019 at 20:51)</a>:</h4>
<p>and yet to my eye there are relatively simple variants that one might argue are coupled to the control-flow graph</p>



<a name="159551360"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551360" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551360">(Feb 27 2019 at 20:54)</a>:</h4>
<p>reading over the test now, I admit that the <em>intent</em> of the <code>fn all_previous_tests_may_be_done</code> may have been more about the order in which the components of the tuple are matched</p>



<a name="159551375"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551375" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551375">(Feb 27 2019 at 20:54)</a>:</h4>
<p>rather than the order of the match arms, which is what the text of <a href="https://github.com/rust-lang/rust/issues/58646" target="_blank" title="https://github.com/rust-lang/rust/issues/58646">#58646</a> is talking about</p>



<a name="159551428"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551428" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551428">(Feb 27 2019 at 20:55)</a>:</h4>
<p>That's what the test was for. I don't mind the example that you posted too much since it amounts to us guaranteeing that we don't preemptively test patterns.</p>



<a name="159551452"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551452" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551452">(Feb 27 2019 at 20:55)</a>:</h4>
<p>I don't know how to interpret "don't mind the example",</p>



<a name="159551506"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551506" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551506">(Feb 27 2019 at 20:56)</a>:</h4>
<p>that could mean "it would be fine for the compiler to accept it"</p>



<a name="159551511"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551511" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551511">(Feb 27 2019 at 20:56)</a>:</h4>
<p>There are some more subtle cases around guards where we expose the fact that we sometimes "remember" the result of a test across a guard.</p>



<a name="159551513"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551513" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551513">(Feb 27 2019 at 20:56)</a>:</h4>
<p>or it could mean "it would be fine for us to start rejecting it"</p>



<a name="159551520"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551520" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551520">(Feb 27 2019 at 20:56)</a>:</h4>
<blockquote>
<p>that could mean "it would be fine for the compiler to accept it"</p>
</blockquote>
<p>I mean this</p>



<a name="159551571"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551571" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551571">(Feb 27 2019 at 20:57)</a>:</h4>
<p>okay</p>



<a name="159551581"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551581" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551581">(Feb 27 2019 at 20:57)</a>:</h4>
<p>I also don't mind if we accept that code</p>



<a name="159551617"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551617" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551617">(Feb 27 2019 at 20:57)</a>:</h4>
<p>but I do think it might lead to some interesting question marks when it comes time to attempt formal specification</p>



<a name="159551688"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551688" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551688">(Feb 27 2019 at 20:58)</a>:</h4>
<p>and it might be an interesting experiment to just try adding backwards fake edges?</p>



<a name="159551695"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551695" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551695">(Feb 27 2019 at 20:58)</a>:</h4>
<p>or maybe that's bonkers</p>



<a name="159551711"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551711" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551711">(Feb 27 2019 at 20:59)</a>:</h4>
<p>anyway, that's everything I wanted to get out in the open</p>



<a name="159551732"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551732" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551732">(Feb 27 2019 at 20:59)</a>:</h4>
<p>I really don't want a cyclic cfg for <code>match</code>. It interacts pretty badly with guards.</p>



<a name="159551771"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551771" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551771">(Feb 27 2019 at 20:59)</a>:</h4>
<blockquote>
<p>I really don't want a cyclic cfg for <code>match</code>. It interacts pretty badly with guards.</p>
</blockquote>
<p>yeah I was worried about that. The only alternative I could image would involve having duplicate code paths</p>



<a name="159551860"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551860" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551860">(Feb 27 2019 at 21:00)</a>:</h4>
<p>I think more fake reads would be the better approach to this.</p>



<a name="159551863"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551863" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551863">(Feb 27 2019 at 21:00)</a>:</h4>
<p>and duplicate code paths, if you nest matches, could have bad (code size) blow up (at least in the abstract representation, not the actual machine code)</p>



<a name="159551927"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159551927" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159551927">(Feb 27 2019 at 21:01)</a>:</h4>
<p>oh interesting ... like add fake reads of future patterns, sort of modelling speculative execution</p>



<a name="159552018"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552018" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552018">(Feb 27 2019 at 21:02)</a>:</h4>
<p>the other simple reality is that if we <strong>actually</strong> wanted to make changes to the match code gen, it would probably have to be tied to an edition or something</p>



<a name="159552046"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552046" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552046">(Feb 27 2019 at 21:02)</a>:</h4>
<p>at least that's my guess as to how we could best limit any negative impact.</p>



<a name="159552217"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552217" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552217">(Feb 27 2019 at 21:05)</a>:</h4>
<p>if we're done with nominated issues I have a couple questions</p>



<a name="159552227"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552227" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552227">(Feb 27 2019 at 21:05)</a>:</h4>
<p>I'm done with the nominations</p>



<a name="159552330"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552330" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552330">(Feb 27 2019 at 21:06)</a>:</h4>
<p>the first is related to universes and the temporary return of the leak check: I was working on <a href="https://github.com/rust-lang/rust/issues/57374" target="_blank" title="https://github.com/rust-lang/rust/issues/57374">#57374</a> but the leak check's return has brought it back to pre-Universes levels of diagnostics. I feel I needed some help from Felix to advance</p>



<a name="159552365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552365">(Feb 27 2019 at 21:07)</a>:</h4>
<p>hmm</p>



<a name="159552386"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552386" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552386">(Feb 27 2019 at 21:07)</a>:</h4>
<p>(there's a dedicated topic, where I posted my level of progress, which was somewhat at this point "we need to look at the mir and reimplement basic errors" so that felt wrong-ish)</p>



<a name="159552433"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552433" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552433">(Feb 27 2019 at 21:08)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span>  is there a <code>-Z</code> flag to remove the leak check?</p>



<a name="159552448"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552448" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552448">(Feb 27 2019 at 21:08)</a>:</h4>
<p><code>-Zno-leak-check</code></p>



<a name="159552461"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552461" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552461">(Feb 27 2019 at 21:08)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> could that help you at least have something to run with?</p>



<a name="159552465"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552465" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552465">(Feb 27 2019 at 21:08)</a>:</h4>
<p>thanks Matthew</p>



<a name="159552512"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552512" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552512">(Feb 27 2019 at 21:09)</a>:</h4>
<p>it's also related to other issues (another ICE, etc) so I was wondering when do we think the leak check will be removed again ?</p>



<a name="159552556"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552556" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552556">(Feb 27 2019 at 21:09)</a>:</h4>
<p>(some of these were closed by the PR but we might need to keep an eye on them for when it's removed again)</p>



<a name="159552822"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552822" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552822">(Feb 27 2019 at 21:12)</a>:</h4>
<p>/me is trying to figure out how we missing <a href="https://github.com/rust-lang/rust/issues/46989" target="_blank" title="https://github.com/rust-lang/rust/issues/46989">#46989</a> at last week's T-compiler meeting...</p>



<a name="159552839"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159552839" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159552839">(Feb 27 2019 at 21:12)</a>:</h4>
<p>but yeah <code>-Zno-leak-check</code> will help in at least being able to work on <a href="https://github.com/rust-lang/rust/issues/57374" target="_blank" title="https://github.com/rust-lang/rust/issues/57374">#57374</a>, albeit I'm still unsure on what to do. My last update on it being <a href="#narrow/stream/122657-t-compiler.2Fwg-nll/topic/.2357374.20higher.20ranked.20subtype.20errors/near/157301017" title="#narrow/stream/122657-t-compiler.2Fwg-nll/topic/.2357374.20higher.20ranked.20subtype.20errors/near/157301017">this</a></p>



<a name="159553090"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553090" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553090">(Feb 27 2019 at 21:15)</a>:</h4>
<p>okay I'll see if I can spend some time assisting with <a href="https://github.com/rust-lang/rust/issues/57374" target="_blank" title="https://github.com/rust-lang/rust/issues/57374">#57374</a> tomorrow or friday</p>



<a name="159553117"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553117" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553117">(Feb 27 2019 at 21:15)</a>:</h4>
<p>sorry its been a month of radio silence there</p>



<a name="159553175"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553175" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553175">(Feb 27 2019 at 21:16)</a>:</h4>
<p>but while we're here: Are there other Q's?</p>



<a name="159553428"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553428" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553428">(Feb 27 2019 at 21:19)</a>:</h4>
<p>no need to apologize I was working on another universe issue (which was also fixed temporarily by the leak check return :)</p>



<a name="159553458"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553458" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553458">(Feb 27 2019 at 21:19)</a>:</h4>
<p>the other Q I had was about the bivariant wf bug, if you had pointers on to look for such a test case ?</p>



<a name="159553530"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553530" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553530">(Feb 27 2019 at 21:20)</a>:</h4>
<p>hmm nothing at the moment</p>



<a name="159553534"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553534" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553534">(Feb 27 2019 at 21:20)</a>:</h4>
<p>(esp as we're not sure we can trigger it in code)</p>



<a name="159553557"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553557" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553557">(Feb 27 2019 at 21:20)</a>:</h4>
<p>oh ok</p>



<a name="159553602"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553602" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553602">(Feb 27 2019 at 21:21)</a>:</h4>
<p>and that's all I personally had</p>



<a name="159553728"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553728" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553728">(Feb 27 2019 at 21:23)</a>:</h4>
<p>okay. I'm going to remove the I-nominated tag from <a href="https://github.com/rust-lang/rust/issues/54105" target="_blank" title="https://github.com/rust-lang/rust/issues/54105">#54105</a></p>



<a name="159553764"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553764" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553764">(Feb 27 2019 at 21:23)</a>:</h4>
<p>do we need a P- ?</p>



<a name="159553818"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553818" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553818">(Feb 27 2019 at 21:24)</a>:</h4>
<p>I'm not going to put one on quite yet</p>



<a name="159553893"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553893" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553893">(Feb 27 2019 at 21:25)</a>:</h4>
<p>I want another chance to think about this, and I'll hopefully look at it again next week when I again look at the pile of unprioritized issues.</p>



<a name="159553908"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159553908" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159553908">(Feb 27 2019 at 21:25)</a>:</h4>
<p>I can try looking at it a bit as well</p>



<a name="159554139"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159554139" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159554139">(Feb 27 2019 at 21:28)</a>:</h4>
<p>thanks!</p>



<a name="159554181"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159554181" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159554181">(Feb 27 2019 at 21:28)</a>:</h4>
<p>okay bye everyone</p>



<a name="159554194"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159554194" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159554194">(Feb 27 2019 at 21:28)</a>:</h4>
<p>good afternoon/evening everyone <span aria-label="wave" class="emoji emoji-1f44b" role="img" title="wave">:wave:</span></p>



<a name="159554754"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/weekly%20meeting%202019.02.27/near/159554754" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/weekly.20meeting.202019.2E02.2E27.html#159554754">(Feb 27 2019 at 21:35)</a>:</h4>
<p>also: <span aria-label="tada" class="emoji emoji-1f389" role="img" title="tada">:tada:</span> for <a href="https://github.com/rust-lang/rust/issues/58788" target="_blank" title="https://github.com/rust-lang/rust/issues/58788">#58788</a> <span class="user-mention" data-user-id="116118">@Matthew Jasper</span> :)</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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